Wiring boxes for containing electrical connections are known. Wiring entering a wiring box is typically connected to a particular electrical fixture or receptacle such as a lighting fixture, outlet, or switch. Outlet boxes can be used in exposed-conduit wiring installations where they are exteriorly mounted to a wall, column or ceiling and exposed to various environmental conditions. Wiring boxes typically include a housing and two plates removably attached thereto. These boxes are not sealed and allow water and dirt entry. The housing includes ribs formed with the walls of the housing and plates that have openings along the edges for securely fastening the plates to the housing. The design requires many secondary processes to setup and secure the covering plates to the box.
The UL514A test, directed to electrical boxes and the integrity of the plate attachment to the housing, was used to test multiple part boxes that had a steel strip crimped to the box. The test was intended to ensure that the steel strip remained adhered to the box under various conditions. Although industry requirements dictate that the boxes pass, meeting this standard is difficult with boxes assembled from multiple pieces.
Wiring boxes are often the subject of evaluation by organizations that promulgate standards in connection therewith and one of the standards includes that a wiring box should have a minimum resistance to the environmental forces that are typically applied to the wiring box.
In particular, round outlet boxes often have projections extended from the back wall of the housing, for receiving mounting screws to attach electrical fixtures, outlets, or switches to the box. These projections extend from the back wall into a cavity formed by the housing and occupy portions of the working volume of the box, the volume allocated for an electrician to wire the electrical device into the wiring box and ultimately to house the wires connected by the electrician. Some manufacturers offset the working volume lost to the mounting projections by increasing the size of the box (depth and/or diameter), which increases the material cost of the box.
There remains a need for a box that is more resistant to increased environmental forces and maximizes the working volume of the box without increasing the cost of the box.